buffer: move initialization of buffer prototype into node.js

Instead of exposing it in `lib/internal/buffer.js` after deleting
it from the binding and then do the initialization in
`lib/buffer.js`, which results in an implicit dependency on
the order in which these modules are loaded.

PR-URL: https://github.com/nodejs/node/pull/25292
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/buffer.js

@@ -35,7 +35,22 @@ const {
   swap32: _swap32,
   swap64: _swap64,
   kMaxLength,
-  kStringMaxLength
+  kStringMaxLength,
+  zeroFill: bindingZeroFill,
+
+  // Additional Buffer methods
+  asciiSlice,
+  base64Slice,
+  latin1Slice,
+  hexSlice,
+  ucs2Slice,
+  utf8Slice,
+  asciiWrite,
+  base64Write,
+  latin1Write,
+  hexWrite,
+  ucs2Write,
+  utf8Write
 } = internalBinding('buffer');
 const {
   getOwnNonIndexProperties,
@@ -74,10 +89,6 @@ const { validateString } = require('internal/validators');
 
 const internalBuffer = require('internal/buffer');
 
-const { setupBufferJS } = internalBuffer;
-
-const bindingObj = {};
-
 class FastBuffer extends Uint8Array {}
 FastBuffer.prototype.constructor = Buffer;
 internalBuffer.FastBuffer = FastBuffer;
@@ -88,6 +99,19 @@ for (const [name, method] of Object.entries(internalBuffer.readWrites)) {
   Buffer.prototype[name] = method;
 }
 
+Buffer.prototype.asciiSlice = asciiSlice;
+Buffer.prototype.base64Slice = base64Slice;
+Buffer.prototype.latin1Slice = latin1Slice;
+Buffer.prototype.hexSlice = hexSlice;
+Buffer.prototype.ucs2Slice = ucs2Slice;
+Buffer.prototype.utf8Slice = utf8Slice;
+Buffer.prototype.asciiWrite = asciiWrite;
+Buffer.prototype.base64Write = base64Write;
+Buffer.prototype.latin1Write = latin1Write;
+Buffer.prototype.hexWrite = hexWrite;
+Buffer.prototype.ucs2Write = ucs2Write;
+Buffer.prototype.utf8Write = utf8Write;
+
 const constants = Object.defineProperties({}, {
   MAX_LENGTH: {
     value: kMaxLength,
@@ -104,11 +128,11 @@ const constants = Object.defineProperties({}, {
 Buffer.poolSize = 8 * 1024;
 let poolSize, poolOffset, allocPool;
 
-setupBufferJS(Buffer.prototype, bindingObj);
-
+// A toggle used to access the zero fill setting of the array buffer allocator
+// in C++.
 // |zeroFill| can be undefined when running inside an isolate where we
 // do not own the ArrayBuffer allocator.  Zero fill is always on in that case.
-const zeroFill = bindingObj.zeroFill || [0];
+const zeroFill = bindingZeroFill || [0];
 
 function createUnsafeBuffer(size) {
   return new FastBuffer(createUnsafeArrayBuffer(size));